2-Isopropyl-4-methylthiazole

In short

2-Isopropyl-4-methylthiazole, sold as tropical thiazole, is a sulphur-nitrogen flavour material. JECFA describes a green, herbaceous, vegetable, earthy odour.

What 2-Isopropyl-4-methylthiazole smells like

JECFA, as published by PubChem, describes 2-isopropyl-4-methylthiazole as a colourless to pale yellow liquid with a green, herbaceous, vegetable, earthy odour. PubChem lists tropical thiazole among its synonyms and links it to natural-product databases. Sigma-Aldrich's food-grade listing, which also gives the synonym peach thiazole, describes it as green, nutty, fruity and earthy.

Leading note: Green vegetable
Clear facets: Herbaceous
Supporting facets: Earthy
Character: Sulphurous, potent

What makes 2-Isopropyl-4-methylthiazole distinctive

A green, earthy thiazole whose trade name points to its use in tropical fruit.

How 2-Isopropyl-4-methylthiazole is used

Used in traces in green, vegetable and fruit effects; its trade name refers to tropical-fruit use.

Typical role: modifier (used in small amounts to change the character of a blend).

How 2-Isopropyl-4-methylthiazole differs from similar materials

2-Ethyl-4-methylthiazole: Tropical thiazole is green, herbaceous, vegetable and earthy rather than nutty.
4,5-Dimethyl-2-isobutylthiazole: Geranium thiazole is the earthier, leafier thiazole; this one is fruitier, which is why it is sold as tropical or peach thiazole.

Each difference compares the published descriptions of the two materials. Smell varies with grade, supplier and dilution; compare them side by side on blotters before substituting one for another.

Formulation considerations

Potent; the formulas use it at 0.1%.

Identity and classification

Type: Aroma chemical
Origin: Occurs in nature
Odour family: Green / Fruity
Note position: Top to heart note
Physical form at room temperature: Liquid
Also known as: Tropical thiazole
CAS number: 15679-13-7
Molecular formula: C7H11NS
Molecular weight: 141.24 g/mol
IUPAC name: 4-methyl-2-propan-2-yl-1,3-thiazole

The CAS number, formula and molecular weight are taken from PubChem compound 61808, whose own record lists this CAS number; checked 24 October 2026.

Safety and compliance

Hazard classification of the neat substance, as PubChem summarises it, read 26 October 2026. Companies notifying the ECHA C&L Inventory classify it (1,753 reports): H302 harmful if swallowed (94.4% of reports); H226 flammable liquid and vapor (10.2% of reports). Unless it is harmonised, this is the notifiers' own classification, not a binding one.

This page is general information, not a safety assessment or a specification. Confirm identity, composition, IFRA status and allergen content from your supplier's documents for the lot you hold.

Materials it works with

Grapefruit Mercaptan
Aroma chemical · Citrus / Fruity — grapefruit, sulfurous, juicy, tropical
cis-3-Hexenol
Aroma chemical · Green / Fruity — green, cut grass, leafy, fresh
Paradisamide
Aroma chemical · Fruity / Citrus — guava, grapefruit, rhubarb, cassis

2-Isopropyl-4-methylthiazole is also suggested as a partner on the pages for 2-Ethyl-4-methylthiazole and 4,5-Dimethyl-2-isobutylthiazole.

Used in formulas and accords

Used in 3 published formulas

2-Isopropyl-4-methylthiazole is an ingredient in 2 perfume formulas and 1 accord in the Formula & Accord Library.

Community formulas

Banana Bread
Community Formula · listed as “Tropical Thiazole 0.1%”, at 0.1%
Lychee Accord
Community Formula · Accord · listed as “Tropical Thiazole 0.1%”, at 0.1%

RUŌOD House Originals

Original compositions by RUŌOD House.

Green Pod Theory
RUŌOD House Creation · listed as “2-Isopropyl-4-methylthiazole 1% DPG”, at 1% in DPG

Questions about 2-Isopropyl-4-methylthiazole

Is 2-Isopropyl-4-methylthiazole natural or synthetic?

The molecule occurs in nature. Commercial 2-Isopropyl-4-methylthiazole may be made by synthesis or obtained from natural sources, so check the supplier's specification if the distinction matters to you.

What is the CAS number of 2-Isopropyl-4-methylthiazole?

15679-13-7. It was checked against PubChem on 24 October 2026.

Which published formulas use 2-Isopropyl-4-methylthiazole?

2-Isopropyl-4-methylthiazole is used in 3 published formulas in the RUŌOD Lab Formula & Accord Library: Banana Bread, Green Pod Theory and Lychee Accord. Each is listed with a link under "Used in formulas and accords" on this page.

Sources

PubChem — compound 61808, checked 24 October 2026.
PubChem — GHS classification (the ECHA C&L Inventory notifications and any harmonised EU entry), read 26 October 2026.
PubChem — 2-Isopropyl-4-methylthiazole (CID 61808): JECFA organoleptic description — odour database.
Sigma-Aldrich — 2-isopropyl-4-methylthiazole (W355518) — manufacturer's description.
Olfactory profile: the RUŌOD Lab team's synthesis of the published descriptions above, reviewed 26 October 2026. Evidence: more than one published description. Classification and the short description: revision 1. Descriptions of odour are judgement, not measurement.